The Link Grammar Parser (link-grammar) is a syntactic parser of English, Russian, Arabic, and Persian (and other languages as well), based on link grammar, an original theory of English syntax. Given a sentence, the system assigns to it a syntactic structure, which consists of a set of labelled links connecting pairs of words. The parser also produces a "constituent" (Penn tree-bank style phrase tree) representation of a sentence (showing noun phrases, verb phrases, etc.). The RelEx extension provides dependency-parse output.

STMX is a high-performance Common Lisp library for composable Transactional Memory (TM), a concurrency control mechanism aimed at making concurrent programming easier to write and understand. Instead of traditional lock-based programming, one programs with atomic memory transactions: if a memory transaction returns normally it is committed. If it signals an error, it is rolled back. Transactions can safely run in parallel in different threads, are re-executed from the beginning in case of conflicts or if consistent reads cannot be guaranteed, and effects of a transaction are not visible from other threads until committed. This gives freedom from deadlocks, automatic rollback on failure, and aims to resolve the tension between granularity and concurrency.

Alfa is an experimental programming language. It combines the classic curly-bracket syntax similar to C and JavaScript with multi-clause functions with parameters passed by pattern matching. It is implemented as a translator to Scheme (using Gnu Guile).

LIME is a dynamic programming language with a LISP-like syntax. It features partial function application, eager and lazy evaluation, call-by-value and call-by-reference, macros, reading/writing LIME code as data, a standard library including infinite streams, and an interactive mode with auto-indentation.

Nerd is an attempt to create a cross-platform scripting language that is based on Scheme and easy to embed, extend, and use. It's currently used in video game projects and is interpreted only. There are definite future plans to add a byte-code compiler and VM to it and to write proper documentation.

Arcueid is a C interpreter for Paul Graham's Arc dialect of Lisp. It is intended to be compatible with the Arc 3.1 release, with a simple interface to C, and is easily usable as an embedded interpreter or an extension language.

SSD (Sawfish Session Dialog) is a small and flexible wrapper for session commands. It is intended to be used with Sawfish, but does not require it. It can be configured to use any command for logout, reboot, shutdown, suspend, hibernate, and lock actions. Preset command definitions are available for: KDE4, GNOME2, XFCE4, MATE, and Razor-Qt. It is part of Sawfish-Extras (currently there's only SSD, but more is planned).

GCC-MELT is a high-level domain specific language that eases the development of plugin-like extensions for GCC, the Gnu Compiler Collection. These extensions can analyze or modify GCC internal representations, and can be used for static source code analysis, refactoring, specific warnings, optimizations, etc. The MELT language provides high-level features. Notably, MELT code is translated to C or C++, and can even contain C or C++ code. It includes powerful pattern matching facilities and can manipulate dynamically typed values and raw GCC structures. It enables functional/applicative, object-oriented, reflective programming styles and has a familiar Lisp-like syntax.